Cardiac amyloidosis: approaches to diagnosis and management

State-of-the-Art Imaging of Infiltrative Cardiomyopathies: A Scientific Statement From the American Heart Association

Infiltrative cardiomyopathies comprise a broad spectrum of inherited or acquired conditions caused by deposition of abnormal substances within the myocardium. Increased wall thickness, inflammation, microvascular dysfunction, and fibrosis are the common pathological processes that lead to abnormal myocardial filling, chamber dilation, and disruption of conduction system. Advanced disease presents as heart failure and cardiac arrhythmias conferring poor prognosis. Infiltrative cardiomyopathies are often diagnosed late or misclassified as other more common conditions, such as hypertrophic cardiomyopathy, hypertensive heart disease, ischemic or other forms of nonischemic cardiomyopathies. Accurate diagnosis is also critical because clinical features, testing methodologies, and approach to treatment vary significantly even within the different types of infiltrative cardiomyopathies on the basis of the type of substance deposited. Substantial advances in noninvasive cardiac imaging have enabled accurate and early diagnosis. thereby eliminating the need for endomyocardial biopsy in most cases. This scientific statement discusses the role of contemporary multimodality imaging of infiltrative cardiomyopathies, including echocardiography, nuclear and cardiac magnetic resonance imaging in the diagnosis, prognostication, and assessment of response to treatment.

Molecular Tweezers: Supramolecular Hosts with Broad-Spectrum Biological Applications

Lysine-selective molecular tweezers (MTs) are supramolecular host molecules displaying a remarkably broad spectrum of biologic activities. MTs act as inhibitors of the self-assembly and toxicity of amyloidogenic proteins using a unique mechanism. They destroy viral membranes and inhibit infection by enveloped viruses, such as HIV-1 and SARS-CoV-2, by mechanisms unrelated to their action on protein self-assembly. They also disrupt biofilm of Gram-positive bacteria. The efficacy and safety of MTs have been demonstrated in vitro, in cell culture, and in vivo, suggesting that these versatile compounds are attractive therapeutic candidates for various diseases, infections, and injuries. A lead compound called CLR01 has been shown to inhibit the aggregation of various amyloidogenic proteins, facilitate their clearance in vivo, prevent infection by multiple viruses, display potent anti-biofilm activity, and have a high safety margin in animal models. The inhibitory effect of CLR01 against amyloidogenic proteins is highly specific to abnormal self-assembly of amyloidogenic proteins with no disruption of normal mammalian biologic processes at the doses needed for inhibition. Therapeutic effects of CLR01 have been demonstrated in animal models of proteinopathies, lysosomal-storage diseases, and spinal-cord injury. Here we review the activity and mechanisms of action of these intriguing compounds and discuss future research directions. SIGNIFICANCE STATEMENT: Molecular tweezers are supramolecular host molecules with broad biological applications, including inhibition of abnormal protein aggregation, facilitation of lysosomal clearance of toxic aggregates, disruption of viral membranes, and interference of biofilm formation by Gram-positive bacteria. This review discusses the molecular and cellular mechanisms of action of the molecular tweezers, including the discovery of distinct mechanisms acting in vitro and in vivo, and the application of these compounds in multiple preclinical disease models.

Impaired Extracellular Proteostasis in Patients with Heart Failure

BACKGROUND

Proteostasis impairment and the consequent increase of amyloid burden in the myocardium have been associated with heart failure (HF) development and poor prognosis. A better knowledge of the protein aggregation process in biofluids could assist the development and monitoring of tailored interventions.

AIM

To compare the proteostasis status and protein's secondary structures in plasma samples of patients with HF with preserved ejection fraction (HFpEF), patients with HF with reduced ejection fraction (HFrEF), and age-matched individuals.

METHODS

A total of 42 participants were enrolled in 3 groups: 14 patients with HFpEF, 14 patients with HFrEF, and 14 age-matched individuals. Proteostasis-related markers were analyzed by immunoblotting techniques. Fourier Transform Infrared (FTIR) Spectroscopy in Attenuated Total Reflectance (ATR) was applied to assess changes in the protein's conformational profile.

RESULTS

Patients with HFrEF showed an elevated concentration of oligomeric proteic species and reduced clusterin levels. ATR-FTIR spectroscopy coupled with multivariate analysis allowed the discrimination of HF patients from age-matched individuals in the protein amide I absorption region (1700-1600 cm^-1), reflecting changes in protein conformation, with a sensitivity of 73 and a specificity of 81%. Further analysis of FTIR spectra showed significantly reduced random coils levels in both HF phenotypes. Also, compared to the age-matched group, the levels of structures related to fibril formation were significantly increased in patients with HFrEF, whereas the β-turns were significantly increased in patients with HFpEF.

CONCLUSION

Both HF phenotypes showed a compromised extracellular proteostasis and different protein conformational changes, suggesting a less efficient protein quality control system.

A Review of Cardiac amyloidosis: Presentation, Diagnosis, and Treatment

Amyloidosis is a group of disorders that can affect almost any organ due to the misfolding of proteins with their subsequent deposition in various tissues, leading to various disease manifestations based on the location. When the heart is involved, amyloidosis can manifest with a multitude of presentations such as heart failure, arrhythmias, orthostatic hypotension, syncope, and pre-syncope. Diagnosis of cardiac amyloidosis can be difficult due to the non-specific nature of symptoms and the relative rarity of the disease. Amyloidosis can remain undiagnosed for years, leading to its high morbidity and mortality due to this delay in diagnosis. Newer imaging modalities, such as cardiac magnetic resonance imaging, advanced echocardiography, and biomarkers, make a timely cardiac amyloidosis diagnosis more feasible. Many treatment options are available, which have provided new hope for this patient population. This manuscript will review the pathology, diagnosis, and treatment options available for cardiac amyloidosis and provide a comprehensive overview of this complicated disease process.

Early Left Ventricular Systolic Dysfunction Detected by Two-Dimensional Speckle-Tracking Echocardiography in Young Patients with Congenital Generalized Lipodystrophy

PURPOSE

Congenital generalized lipodystrophy (CGL) is a rare autosomal recessive disorder characterized by the absence of functional adipocytes resulting in ectopic lipid storage, metabolic disorders and early cardiovascular disease. Two-dimensional speckle-tracking (2D-STE) allows the detection of early abnormalities in myocardial function. We aimed to evaluate myocardial deformation in a large sample of CGL patients using 2D-STE.

PATIENTS AND METHODS

A cross-sectional study of 22 patients with CGL and 22 healthy subjects, matched for sex and age, was conducted from 2013 to 2018. All participants had undergone standard conventional echocardiography (ECHO) and 2D-STE. Determination of blood glucose, lipids, insulin, and leptin were performed in all CGL patients.

RESULTS

In the CGL group the mean age was 14.6±10.7 years where 68.2% (n=15) were younger than 18 years old. All the patients had hypoleptinemia, 95.4% (21/22) low HDL-c, 86.4% (19/22) hypertriglyceridemia, 68.2% (15/22) diabetes, 50% (11/22) hepatic steatosis, 41% (9/22) insulin resistance, 41% (9/22) hypercholesterolemia, and 18.2% (4/22) hypertension. ECHO showed that 36.6% (8/22) of CGL patients presented diastolic dysfunction, 31.8% (7/22) left ventricular hypertrophy (LVH), 27.3% (6/22) increased left atrial volume index (LAVI), and 18.2% (4/22) increased left ventricular systolic diameter (LVDS) but normal ejection fraction (EF), whether using 2D-STE, 68.2% (15/22) of CGL patients showed abnormal global longitudinal strain (GLS) (p<0.01), and in almost LV segments. Positive association between abnormal GLS and A1c (r=0.57, p=0.005), glucose (r=0.5, p=0.018) and basal insulin (r= 0.69, p= 0.024), and negative association with leptin (r = -0.51, p = 0.005) were found in these patients.

CONCLUSION

The 2D-STE revealed precocious left ventricular systolic dysfunction in a young CGL population with normal systolic function by ECHO. Early exposure to common metabolic abnormalities as insulin resistance, hyperglycemia, and hypoleptinemia must be involved in myocardial damage in these patients.

Quadravalvular Noninfectious Endocarditis

Nonbacterial thrombotic endocarditis is characterized by sterile thrombi on cardiac valves. This report describes the case of nonbacterial endocarditis without pathologic findings of fibrin or platelet deposition. Quadrivalvular endocarditis was found to be due to immunoglobulin M heavy chain deposition. This was a case of nonbacterial, nonthrombotic quadrivalvular endocarditis, which was termed noninfective endocarditis. (Level of Difficulty: Intermediate.)

Role of Right Ventricular Strain Measured by Two-Dimensional Echocardiography in the Diagnosis of Cardiac Amyloidosis

BACKGROUND

Cardiac amyloidosis (CA) causes restrictive cardiomyopathy usually associated with a poor prognosis. Two subtypes predominate: systemic light-chain CA (ALCA) and transthyretin-derived CA (either wild type transthyretin amyloidosis [TTRwt] or mutant transthyretin amyloidosis [TTRm]). Left ventricular (LV) apical sparing has been extensively studied using speckle-tracking echocardiography for diagnosis, but the right ventricular (RV) deformation pattern has not been described. The aims of this study were to characterize RV involvement in patients with CA and to identify parameters that may help in the differential diagnosis between ALCA and transthyretin-derived CA subtypes.

METHODS

Seventy-eight patients with CA (47 with ALCA, 20 with TTRwt, and 11 with TTRm) and 24 healthy control subjects were included. Global longitudinal strain (GLS) was analyzed in 16 LV and six RV segments. LV and RV apical ratios (ARs) were obtained. GLS was expressed as an absolute value.

RESULTS

LV GLS and free-wall RV longitudinal strain were impaired in all patients (LV GLS: 11.9 ± 2.9% in ALCA, 12.5 ± 3.8% in TTRwt, 14.9 ± 2.7% in TTRm, and 21.9 ± 2.6% in control subjects [P < .01]; free-wall RV longitudinal strain: 13.1 ± 6.8%, 14.9 ± 4.5%, 17.2 ± 3.4%, and 22.1 ± 3.1%, respectively [P < .01]). LV and RV ARs were higher in ALCA compared with both TTRwt, TTRm, and control subjects (LV AR: 1.1 ± 0.2, 0.8 ± 0.2, 0.9 ± 0.1, and 0.7 ± 0.1, respectively [P < .001]; RV AR: 1.1 ± 0.2, 0.6 ± 0.2, 0.6 ± 0.1, and 0.6 ± 0.1, respectively [P < .001]). Cutoff values of LV AR > 0.96 and RV AR > 0.8 showed high accuracy to differentiate between ALCA and transthyretin-derived CA.

CONCLUSIONS

RV dysfunction is common in patients with CA. Analysis of RV strain showed an apical sparing pattern, as previously described in the left ventricle, with a higher AR as a specific finding in patients with ALCA. RV AR may be a parameter that can differentiate the subtypes of amyloidosis on the basis of speckle-tracking echocardiographic analysis.

Immunoglobulin light chain amyloidosis: 2018 Update on diagnosis, prognosis, and treatment

DISEASE OVERVIEW

Immunoglobulin light chain amyloidosis is a clonal, nonproliferative plasma cell disorder in which fragments of immunoglobulin light or heavy chain are deposited in tissues. Clinical features depend on organs involved but can include restrictive cardiomyopathy, nephrotic syndrome, hepatic dysfunction, peripheral/autonomic neuropathy, and "atypical multiple myeloma."

DIAGNOSIS

Tissue biopsy stained with Congo red demonstrating amyloid deposits with apple-green birefringence is required for diagnosis. Invasive organ biopsy is not required because amyloid deposits can be found in bone marrow, salivary gland, or subcutaneous fat aspirate in 85% of patients. Verification that amyloid is composed of immunoglobulin light chains is mandatory. The gold standard is laser capture mass spectroscopy.

PROGNOSIS

N-terminal pro-brain natriuretic peptide (NT-proBNP), serum troponin T, and difference between involved and uninvolved immunoglobulin free light chain values are used to classify patients into four groups of similar size; median survivals are 94.1, 40.3, 14.0, and 5.8 months.

THERAPY

All patients with a systemic amyloid syndrome require therapy to prevent deposition of amyloid in other organs and prevent progressive organ failure. Stem cell transplant (SCT) is preferred, but only 20% of patients are eligible. Requirements for safe SCT include systolic blood pressure >90 mm Hg, troponin T < 0.06 ng/mL, age < 70 years, and serum creatinine ≤1.7 mg/dL. Nontransplant candidates can be offered melphalan-dexamethasone or cyclophosphamide-bortezomib-dexamethasone. Daratumumab appears to be highly active in AL amyloidosis. Antibodies designed to dissolve existing amyloid deposits are under study.

FUTURE CHALLENGES

Delayed diagnosis remains a major obstacle to initiating effective therapy.

EDUCATIONAL OBJECTIVES

Upon completion of this educational activity, participants will be better able to: Master recognition of clinical presentations that should raise suspicion of amyloidosis. Understand simple techniques for confirming the diagnosis and providing material to classify the protein subunit. Recognize that a tissue diagnosis of amyloidosis does not indicate whether the amyloid is systemic or of immunoglobulin light chain origin. Understand the roles of the newly introduced chemotherapeutic and investigational antibody regimens for the therapy of light chain amyloidosis.

Pulmonary Fat Embolism and Coronary Amyloidosis

Patient: Male, 72

Final Diagnosis: Fat lung embolism

Symptoms: Dyspnea

Medication: —

Clinical Procedure: —

Specialty: Orthpedics and Traumatology

Diagnostic accuracy of bone scintigraphy in the assessment of cardiac transthyretin-related amyloidosis: a bivariate meta-analysis

PURPOSE

Cardiac transthyretin-related amyloidosis (ATTR) is a progressive and fatal cardiomyopathy. The diagnosis of this disease is frequently delayed or missed due to the limited specificity of echocardiography. An increasing amount of data in the literature demonstrate the ability of bone scintigraphy with bone-seeking radiopharmaceuticals to detect myocardial amyloid deposits, in particular in patients with ATTR. Therefore we performed a systematic review and bivariate meta-analysis of the diagnostic accuracy of bone scintigraphy in patients with suspected cardiac ATTR.

METHODS

A comprehensive computer literature search of studies published up to 30 November 2017 on the role of bone scintigraphy in patients with ATTR was performed using the following search algorithm: (a) "amyloid" OR "amyloidosis" AND (b) "TTR" OR "ATTR" OR "transthyretin" AND (c) "scintigraphy" OR "scan" OR "SPECT" OR "SPET" OR "bone" OR "skeletal" OR "skeleton" OR "PYP" OR "DPD" OR "HMDP" OR "MDP" OR "HDP". Pooled sensitivity, specificity, positive and negative likelihood ratios (LR+ and LR-) and diagnostic odds ratio (DOR) of bone scintigraphy were calculated.

RESULTS

The meta-analysis of six selected studies on bone scintigraphy in cardiac ATTR including 529 patients provided the following results: sensitivity 92.2% (95% CI 89-95%), specificity 95.4% (95% CI 77-99%), LR+ 7.02 (95% CI 3.42-14.4), LR- 0.09 (95% CI 0.06-0.14), and DOR 81.6 (95% CI 44-153). Mild heterogeneity was found among the selected studies.

CONCLUSION

Our evidence-based data demonstrate that bone scintigraphy using technetium-labelled radiotracers provides very high diagnostic accuracy in the non-invasive assessment of cardiac ATTR.

Multidisciplinary approach to cardiac and pulmonary vascular disease risk assessment in liver transplantation: An evaluation of the evidence and consensus recommendations

Liver transplant (LT) candidates today are older, have greater medical severity of illness, and have more cardiovascular comorbidities than ever before. In addition, there are specific cardiovascular responses in cirrhosis that can be detrimental to the LT candidate. Cirrhotic cardiomyopathy, a condition characterized by increased cardiac output and a reduced ventricular response to stress, is present in up to 30% of patients with cirrhosis, thus challenging perioperative management. Current noninvasive tests that assess for subclinical coronary and myocardial disease have low sensitivity, and altered hemodynamics during the LT surgery can unmask latent cardiovascular disease either intraoperatively or in the immediate postoperative period. Therefore, this review, assembled by a group of multidisciplinary experts in the field and endorsed by the American Society of Transplantation Liver and Intestine and Thoracic and Critical Care Communities of Practice, provides a critical assessment of the diagnosis of cardiac and pulmonary vascular disease and interventions aimed at managing these conditions in LT candidates. Key points and practice-based recommendations for the diagnosis and management of cardiac and pulmonary vascular disease in this population are provided to offer guidance for clinicians and identify gaps in knowledge for future investigations.

2017 Comprehensive Update of the Canadian Cardiovascular Society Guidelines for the Management of Heart Failure

Since the inception of the Canadian Cardiovascular Society heart failure (HF) guidelines in 2006, much has changed in the care for patients with HF. Over the past decade, the HF Guidelines Committee has published regular updates. However, because of the major changes that have occurred, the Guidelines Committee believes that a comprehensive reassessment of the HF management recommendations is presently needed, with a view to producing a full and complete set of updated guidelines. The primary and secondary Canadian Cardiovascular Society HF panel members as well as external experts have reviewed clinically relevant literature to provide guidance for the practicing clinician. The 2017 HF guidelines provide updated guidance on the diagnosis and management (self-care, pharmacologic, nonpharmacologic, device, and referral) that should aid in day-to-day decisions for caring for patients with HF. Among specific issues covered are risk scores, the differences in management for HF with preserved vs reduced ejection fraction, exercise and rehabilitation, implantable devices, revascularization, right ventricular dysfunction, anemia, and iron deficiency, cardiorenal syndrome, sleep apnea, cardiomyopathies, HF in pregnancy, cardio-oncology, and myocarditis. We devoted attention to strategies and treatments to prevent HF, to the organization of HF care, comorbidity management, as well as practical issues around the timing of referral and follow-up care. Recognition and treatment of advanced HF is another important aspect of this update, including how to select advanced therapies as well as end of life considerations. Finally, we acknowledge the remaining gaps in evidence that need to be filled by future research.

Immunoglobulin light chain amyloidosis: 2016 update on diagnosis, prognosis, and treatment

DISEASE OVERVIEW

Immunoglobulin light chain amyloidosis is a clonal, nonproliferative plasma cell disorder in which fragments of immunoglobulin light chain are deposited in tissues. Clinical features depend on organs involved but can include restrictive cardiomyopathy, nephrotic syndrome, hepatic failure, peripheral/autonomic neuropathy, and atypical multiple myeloma.

DIAGNOSIS

Tissue biopsy stained with Congo red demonstrating amyloid deposits with applegreen birefringence is required for diagnosis. Invasive organ biopsy is not required because amyloid deposits can be found in bone marrow biopsy or subcutaneous fat aspirate in 85% of patients. Verification that amyloid is composed of immunoglobulin light chains is mandatory.

PROGNOSIS

N-terminal pro-brain natriuretic peptide (NTproBNP), serum troponin T, and difference between involved and uninvolved immunoglobulin free light chain values are used to classify patients into four groups of similar size; median survivals are 94.1, 40.3, 14.0, and 5.8 months.

THERAPY

All patients with a systemic amyloid syndrome require therapy to prevent deposition of amyloid in other organs and prevent progressive organ failure of involved sites. Stem cell transplant (SCT) is preferred, but only 20% of patients are eligible. Requirements for safe SCT include systolic blood pressure >90 mmHg, troponin T <0.06 ng mL21, age <70 years, and serum creatinine 1.7 mg dL21. Nontransplant candidates can be offered melphalan-dexamethasone or cyclophosphamide-bortezomib-dexamethasone. Other combinations of chemotherapy with agents such as cyclophosphamide-thalidomide (or lenalidomide)-dexamethasone, bortezomib-dexamethasone, and melphalan-prednisone-lenalidomide have documented activity. Antibodies designed to dissolve existing amyloid deposits are under study for previously treated and untreated patients. Late diagnosis remains a major obstacle to initiating effective therapy. Am. J. Hematol., 2016. © 2016 Wiley Periodicals, Inc. Am. J. Hematol. 91:948-956, 2016. © 2016 Wiley Periodicals, Inc.

Transthyretin amyloid neuropathy has earlier neural involvement but better prognosis than primary amyloid counterpart: an answer to the paradox?

OBJECTIVE

To systematically compare transthyretin with primary amyloid neuropathy to define their natural history and the underlying mechanisms for differences in phenotype and natural history.

METHODS

All patients with defined amyloid subtype and peripheral neuropathy who completed autonomic testing and electromyography at Mayo Clinic Rochester between 1993 and 2013 were included. Medical records were reviewed for time of onset of defined clinical features. The degree of autonomic impairment was quantified using the composite autonomic severity scale. Comparisons were made between acquired and inherited forms of amyloidosis.

RESULTS

One hundred one cases of amyloidosis with peripheral neuropathy were identified, 60 primary and 41 transthyretin. Twenty transthyretin cases were found to have Val30Met mutations; 21 had other mutations. Compared to primary cases, transthyretin cases had longer survival, longer time to diagnosis, higher composite autonomic severity scale scores, greater reduction of upper limb nerve conduction study amplitudes, more frequent occurrence of weakness, and later non-neuronal systemic involvement. Four systemic markers (cardiac involvement by echocardiogram, weight loss > 10 pounds, orthostatic intolerance, fatigue) in combination were highly predictive of poor survival in both groups.

INTERPRETATION

These findings suggest that transthyretin has earlier and greater predilection for neural involvement and more delayed systemic involvement. The degree and rate of systemic involvement is most closely related to prognosis. Ann Neurol 2016;80:401-411.

Diagnostic approach to cardiac amyloidosis: A case report

The authors present a case of systemic amyloidosis with cardiac involvement. We discuss the need for a high level of suspicion to establish a diagnosis, diagnostic techniques and treatment options. Our patient was a 78-year-old man with chronic renal disease and atrial fibrillation admitted with acute decompensated heart failure of unknown cause. The transthoracic echocardiogram revealed severely impaired left ventricular function with phenotypic overlap between hypertrophic and restrictive cardiomyopathy. After an extensive diagnostic workup, which included an abdominal fat pad biopsy, the final diagnosis was amyloidosis.

Contribution of Electrocardiogram in the Differentiation of Cardiac Amyloidosis and Nonobstructive Hypertrophic Cardiomyopathy

Due to similar manifestations of hypertensive ventricular walls and abnormal ventricular compliance, it is difficult to differentiate cardiac amyloidosis (CA) and nonobstructive hypertrophic cardiomyopathy (NOHCM) clinically. The purpose of the study was to investigate the value of electrocardiography (ECG) in the differentiation of the two diseases.

METHODS

We enrolled 46 consecutive patients with CA and 64 patients with NOHCM and compared their ECG characteristics.Compared with NOHCM patients, the ECG of CA patients showed more low voltage on limb leads (50% versus 1.6%), atrioventricular block (21.7% versus 4.7%), pseudo-infarct pattern (84.8% versus 39.1%), and longer QRS duration (104 ± 25 versus 98 ± 14 ms) (all P < 0.05). The QRS complex voltage of avR demonstrated the highest diagnostic performance (sensitivity 89%, specificity 94%, cut-off value 0.45mV) as assessed by ROC analysis. The combination of the R wave voltage of I and avR reached a sensitivity of 95% and a specificity of 87% for the diagnosis of amyloidosis.Compared with NOHCM patients, CA patients showed more ECG characteristics of low voltage on limb leads, pseudo-infarct pattern, atrioventricular block, and longer QRS duration. The combination of the R wave voltage of I, avR, and QRS was of diagnostic value in the differentiation of CA from NOHCM.

Cardiac Amyloidosis Presenting With Cardiogenic Shock

Cardiac amyloidosis is an infiltrative disorder of the myocardium. It is the result of one of 4 types of amyloidosis: primary systemic (immunoglobulin light chain), secondary, familial (hereditary), or senile. Cardiac amyloidosis ultimately causes congestive heart failure due to irreversible restrictive cardiomyopathy. Because of the rapid progression of the disease, early recognition and determination of underlying etiology are important for tailored therapy. Current interventions range from conservative heart failure management to autologous stem cell and heart transplantation. We present a case of cardiac amyloidosis accompanying undiagnosed multiple myeloma to illustrate the rapid progression of the disease and the complexities of diagnosing and treating this disorder.

Immunoglobulin light chain amyloidosis: 2014 update on diagnosis, prognosis, and treatment

DISEASE OVERVIEW

Immunoglobulin light chain amyloidosis is a clonal, nonproliferative plasma cell disorder in which fragments of immunoglobulin light chain are deposited in tissues. Clinical features depend on organs involved but can include restrictive cardiomyopathy, nephrotic syndrome, hepatic failure, peripheral/autonomic neuropathy, and atypical multiple myeloma.

DIAGNOSIS

Tissue biopsy stained with Congo red demonstrating amyloid deposits with apple-green birefringence is required for diagnosis. Invasive organ biopsy is not required because amyloid deposits can be found in bone marrow biopsy or subcutaneous fat aspirate in 85% of patients. Verification that amyloid is composed of immunoglobulin light chains is mandatory.

PROGNOSIS

N-terminal pro-brain natriuretic peptide (NT-proBNP), serum troponin T, and difference between involved and uninvolved immunoglobulin free light chain values are used to classify patients into four groups of similar size; median survivals are 94.1, 40.3, 14.0, and 5.8 months.

THERAPY

All patients with a systemic amyloid syndrome require therapy to prevent deposition of amyloid in other organs and prevent progressive organ failure of involved sites. Stem cell transplant (SCT) is preferred, but only 20% of patients are eligible. Requirements for safe SCT include NT-proBNP <5,000 ng/mL, troponin T <0.06 ng/mL, age <70 years, <3 organs involved, and serum creatinine ≤1.7 mg/dL. Nontransplant candidates can be offered melphalan-dexamethasone or cyclophosphamide-bortezomib-dexamethasone. Other combinations of chemotherapy with agents such as cyclophosphamide-thalidomide (or lenalidomide)-dexamethasone, bortezomib-dexamethasone, and melphalan-prednisone-lenalidomide have documented activity. Future Challenges: Late diagnosis remains a major obstacle to initiating effective therapy. Recognizing the presenting syndromes is necessary for improving survival.

Nuclear imaging modalities for cardiac amyloidosis

Amyloidosis is a heterogeneous group of diseases characterized by localized or systemic deposition of insoluble extracellular fibrillary proteins in organs and tissues. Several types of amyloid can infiltrate the heart resulting in a restrictive cardiomyopathy, heart failure, and atrial and ventricular arrhythmias. Scintigraphy is a noninvasive method that may facilitate early diagnosis, distinguish various forms of cardiac amyloid, and may be useful in following disease burden. The amyloid-specific tracers presented in this article have been used with planar imaging and/or single-photon emission computed tomography. To date, there are no approved cardiac amyloid tracers although investigational tracers are currently under examination. This article serves to review the current nuclear imaging modalities available in the detection of cardiac amyloid.

Immunoglobulin light chain amyloidosis: 2013 update on diagnosis, prognosis, and treatment

DISEASE OVERVIEW

Immunoglobulin (Ig) light chain amyloidosis is a clonal, nonproliferative plasma cell disorder in which fragments of Ig light chain are deposited in tissues. Clinical features depend on organs involved but can include restrictive cardiomyopathy, nephrotic syndrome, hepatic failure, peripheral/autonomic neuropathy, and atypical multiple myeloma.

DIAGNOSIS

Tissue biopsy stained with Congo red demonstrating amyloid deposits with apple-green birefringence is required for diagnosis. Invasive organ biopsy is not required because amyloid deposits can be found in bone marrow biopsy or subcutaneous fat aspirate in 85% of patients. Verification that amyloid is of immunoglobulin origin is mandatory.

PROGNOSIS

N-terminal pro-brain natriuretic peptide (NT-proBNP), serum troponin T, and immunoglobulin free light chain values are used to classify patients into four groups of similar size; median survivals are 94.1, 40.3, 14.0, and 5.8 months.

THERAPY

All patients with a visceral amyloid syndrome require therapy to prevent deposition of amyloid in other viscera and prevent progressive organ failure of involved sites. Stem cell transplant (SCT) is preferred, but only 20% of patients are eligible. Requirements for safe SCT include NT-proBNP <5,000 ng/mL, troponin T < 0.06 ng/mL, age <70 years, <3 organs involved, and serum creatinine ≤1.7 mg/dL. Nontransplant candidates can be offered melphalan-dexamethasone. Pomalidomide appears to have activity, as do other combinations of chemotherapy with agents such as cyclophosphamide-thalidomide (or lenalidomide or bortezomib)-dexamethasone, bortezomib-dexamethasone, and melphalan-prednisone-lenalidomide.

FUTURE CHALLENGES

Late diagnosis remains a major obstacle to initiating effective therapy when organ dysfunction is still recoverable. Recognizing the presenting syndromes is necessary for improving survival.

Primary systemic amyloidosis and high levels of Angiotensin-converting enzyme: two case reports

Infiltrative heart diseases are caused by a heterogeneous group of disorders; amyloidosis and sarcoidosis are two frequent causes of myocardial infiltration, which differ in clinical and biological outcome and treatment issues. The presence of high levels of angiotensin-converting enzyme (ACE) in a patient with infiltrative heart disease may increase suspicion of sarcoidosis. Nevertheless, no mention about increased ACE levels in extracerebral primary systemic amyloidosis is available. We present two cases of primary systemic amyloidosis, which are cardiac involvement and elevated ACE levels.

Molecular imaging of amyloidosis: will the heart be the next target after the brain?

Amyloidosis is a heterogeneous group of diseases with a common feature of extracellular deposition and infiltration of different types of amyloid fibrils in various organs. For example, Alzheimer's disease is characterized by deposition of amyloid β in the brain. Radiolabeled positron emission tomography (PET) tracers, mainly derivatives of thioflavin-T, were recently introduced for identification of amyloid β plaques in Alzheimer's patients. Such advances of amyloid β plaque imaging of the brain may shed light into imaging of other organs in amyloidosis patients, such as the heart. Cardiac infiltration of amyloid confers poor clinical outcomes, which renders early diagnosis for appropriate clinical management. At present, nuclear imaging of cardiac amyloidosis is predominantly accomplished with bone-seeking radiotracers, such as 99m-technetium-labeled pyrophosphate ((99m)Tc-PYP), 99m-technetium-methylene diphosphonate ((99m)Tc-MDP), and 99m-technetium-3,3,-diphosphono-1,2-propanodicarboxylic acid ((99m)Tc-DPD), with conflicting results in terms of diagnostic performance, with the exception for (99m)Tc-DPD, which may differentiate light-chain amyloidosis from transthyretin-related cardiac amyloidosis. Although other non-bone-seeking radiotracers such as iodine-123-labeled amyloid P component ((123)I-SAP), 123-iodine-Meta-iodobenzylguanidine ((123)I-mIBG), 99m-technetium-labeled protease inhibitor, and indium-111-labeled amyloid antibodies have also shown some success in identifying cardiac amyloidosis, the future, however, may lie in labeling derivatives of thioflavin-T. With the recent success of visualizing deposition of amyloid β in the brain, the US Food and Drug Administration-approved PET imaging agent (18)F-florbetapir may be used to target cardiac amyloidosis next.

Value of electrocardiogram in the differentiation of hypertensive heart disease, hypertrophic cardiomyopathy, aortic stenosis, amyloidosis, and Fabry disease

Left ventricular hypertrophy is 1 of the most frequent cardiac manifestations associated with an unfavorable prognosis. However, many different causes of left ventricular hypertrophy exist. The aim of the present study was to assess the diagnostic value of common electrocardiographic (ECG) parameters to differentiate Fabry disease (FD), amyloidosis, and nonobstructive hypertrophic cardiomyopathy (HC) from hypertensive heart disease (HHD) and aortic stenosis (AS). In 94 patients with newly diagnosed FD (n = 17), HHD (n = 20), amyloidosis (n = 17), AS (n = 20), and HC (n = 20), common ECG parameters were analyzed and tested for their diagnostic value. A stepwise approach including the Sokolow-Lyon index, corrected QT duration, and PQ interval minus P-wave duration in lead II to overcome P-wave abnormalities was applied. A corrected QT duration <440 ms in combination with a PQ interval minus P-wave duration in lead II <40 ms was 100% sensitive and 99% specific for the diagnosis of FD, whereas a corrected QT duration >440 ms and a Sokolow-Lyon index ≤1.5 mV were found to have a sensitivity and specificity of 85% and 100%, respectively, for the diagnosis of amyloidosis and differentiation from HC, AS, and HHD. Moreover, a novel index ([PQ interval minus P-wave duration in lead II multiplied by corrected QT duration]/Sokolow-Lyon index) proved to be highly diagnostic for the differentiation of amyloidosis (area under the curve 0.92) and FD (area under the curve 0.91) by receiver operator characteristic analysis. In conclusion, a combined analysis of PQ interval minus P-wave duration in lead II, corrected QT duration, and Sokolow-Lyon index proved highly sensitive and specific in the differentiation of FD, amyloidosis, and HC compared to HHD and AS. Analysis of these easy-to-assess ECG parameters may be of substantial help in the diagnostic workup of these 5 conditions.

Transthyretin cardiac amyloidoses in older North Americans

The amyloidoses are a group of hereditary or acquired disorders caused by the extracellular deposition of insoluble protein fibrils that impair tissue structure and function. All amyloidoses result from protein misfolding, a common mechanism for disorders in older persons, including Alzheimer's disease and Parkinson's disease. Abnormalities in the protein transthyretin (TTR), a serum transporter of thyroxine and retinol, is the most common cause of cardiac amyloidoses in elderly adults. Mutations in TTR can result in familial amyloidotic cardiomyopathy, and wild-type TTR can result in senile cardiac amyloidosis. These underdiagnosed disorders are much more common than previously thought. The resulting restrictive cardiomyopathy can cause congestive heart failure, arrhythmias, and advanced conduction system disease. Although historically difficult to make, the diagnosis of TTR cardiac amyloidosis has become easier in recent years with advances in cardiac imaging and more widespread use of genetic analysis. Although therapy has largely involved supportive medical care, avoidance of potentially toxic agents, and rarely organ transplantation, the near future brings the possibility of targeted pharmacotherapies designed to prevent TTR misfolding and amyloid deposition. Because these disease-modifying agents are designed to prevent disease progression, it has become increasingly important that older persons with TTR amyloidosis be expeditiously identified and considered for enrollment in clinical registries and trials.

Potent kinetic stabilizers that prevent transthyretin-mediated cardiomyocyte proteotoxicity

A valine-to-isoleucine mutation at position 122 of the serum protein transthyretin (TTR), found in 3 to 4% of African Americans, alters its stability, leading to amyloidogenesis and cardiomyopathy. In addition, 10 to 15% of individuals older than 65 years develop senile systemic amyloidosis and cardiac TTR deposits because of wild-type TTR amyloidogenesis. Although several drugs are in development, no approved therapies for TTR amyloid cardiomyopathy are yet available, so the identification of additional compounds that prevent amyloid-mediated cardiotoxicity is needed. To this aim, we developed a fluorescence polarization-based high-throughput screen and used it to identify several new chemical scaffolds that target TTR. These compounds were potent kinetic stabilizers of TTR and prevented TTR tetramer dissociation, partial unfolding, and aggregation of both wild type and the most common cardiomyopathy-associated TTR mutant, V122I-TTR. High-resolution co-crystal structures and characterization of the binding energetics revealed how these diverse structures bound to tetrameric TTR. These compounds effectively inhibited the proteotoxicity of V122I-TTR toward human cardiomyocytes. Several of these ligands stabilized TTR in human serum more effectively than diflunisal, which is a well-studied inhibitor of TTR aggregation, and may be promising leads for the treatment or prevention of TTR-mediated cardiomyopathy.

Coexistent asymptomatic myeloma and hereditary cardiac amyloidosis: an unusual case of heart failure

A 76-year-old Afro-Caribbean man presenting with heart failure was diagnosed with isolated cardiac amyloid. He had evidence of myeloma on bone marrow biopsy suggesting AL amyloid, the commonest type of systemic amyloidosis, as the underlying cause. He had no other myeloma-related organ damage. However, endocardial biopsy revealed amyloid fibrils composed of transthyretin and genetic typing established heterozygozity for the valine to isoleucine mutation at position 122 (Val122Ile). The diagnosis was therefore hereditary systemic amyloidosis as a result of a genetic transthyretin variant (ATTR) causing cardiac amyloidosis and coexistent asymptomatic myeloma. This requires symptomatic treatment of heart failure only. This article discusses a rare cause of heart failure and uses this case to illustrate that histological confirmation of the amyloid-causing protein is essential. Mistaken assumption of AL amyloid could have resulted in inappropriate cytotoxic therapy targeting the plasma cell clone.

Primary systemic amyloidosis presenting as constrictive pericarditis

The most frequent presentation of cardiac amyloidosis is with endomyocardial deposition, and resultant restrictive cardiomyopathy. We present a case of primary systemic amyloidosis causing constrictive pericarditis (CP) and congestive heart failure without clinical evidence of endomyocardial deposition. A comprehensive evaluation by noninvasive and invasive studies facilitated the differentiation of CP from restrictive cardiomyopathy and the patient was effectively treated with pericardectomy. To our knowledge, this is the first documented case of primary systemic amyloidosis causing selective CP with successful antemortem diagnosis and treatment in a young man.

Immunoglobulin light chain amyloidosis: 2011 update on diagnosis, risk-stratification, and management

Immunoglobulin (Ig) light chain amyloidosis is a clonal but nonproliferative plasma cell disorder in which fragments of an Ig light chain are deposited in tissues. The clinical features depend on the organs involved but can include restrictive cardiomyopathy, nephrotic syndrome, hepatic failure, and peripheral/autonomic neuropathy. Tissue biopsy stained with Congo red demonstrating amyloid deposits with apple-green birefringence is required for diagnosis. Invasive organ biopsy is not required because amyloid deposits can be found in bone marrow biopsy or subcutaneous fat aspirate in 85% of patients. N-terminal pro-brain natriuretic peptide and serum troponin T values are used to classify patients into three groups of approximately equal size; median survivals are 26.4, 10.5, and 3.5 months, respectively. All patients with a visceral amyloid syndrome require therapy to prevent deposition of amyloid in other viscera and to prevent progressive organ failure of involved sites. Stem cell transplant (SCT) is a preferred technique, but only 20% of patients are eligible. Requirements for safe SCT include mild or no cardiac involvement, troponin T value <0.06 ng/mL, age younger than 70 years, <3 organs involved, and serum creatinine value ≤1.7 mg/dL. Nontransplant candidates can be offered melphalan-dexamethasone. Pomalidomide appears to have activity, as do other combinations of chemotherapy with agents such as cyclophosphamide-thalidomide-dexamethasone, bortezomib-dexamethasone, and melphalan-prednisone-lenalidomide. Late diagnosis remains a major obstacle to initiating effective therapy when organ dysfunction is still recoverable. Recognizing the presenting syndromes is necessary for improvement in survival.